Alt Season Index — ETH/BTC Momentum
Measures how many top-50 altcoins are outperforming Bitcoin. A score above 75 signals alt season.
How the Index Is Calculated
The Alt Season Index counts how many of the top 50 cryptocurrencies (excluding Bitcoin) have outperformed Bitcoin over the past 7 days. If 75% or more (≥37 coins) outperform BTC, it's declared Alt Season. The chart shows the ETH/BTC ratio as a proxy — ETH historically leads altcoin rotation cycles.
When to Use This Index
This index is most useful as a positioning tool, not a buy/sell signal. A score above 75 might confirm that alt season is underway — but catching it late at the top is dangerous. The best entries are when the index is rising from 25-50: early rotation is beginning, risk/reward is highest. When it reads 90+, most of the move is priced in.
Alt Season Warning Signs
Every alt season ends. Warning signs include: Tier-1 alts (ETH, SOL) breaking down first while smaller caps still pump; social media becoming overwhelmingly bullish on speculative tokens; new wallets opening at record rates; and BTC dominance starting to recover. Watching 2-3 of these signals align is a strong caution signal.